What do you mean by big wrench? I use a 12" adjustable wrench, and have proven that bigger is better.
I agree that the vice is
an answer... However, I recently removed a freewheel from a 30 year old bike, and have removed several others from old bikes, and I have never needed a vice.
I sit in a chair, and set the wheel in front of me, just like it was on the bike standing up... I put the tool in, place the wrench so that I can apply pressure downward and push down. Sometimes it will take some time, sometimes some light hammering with the heel of my hand or a rubber mallet.
If one were really tough, I would even try to work with someone else and stand on the end of the wrench.
There may be alternatives...
